Shifts of attention within working memory based on retroactive cues (retro-cues) were shown to facilitate performance in working memory tasks. It was suggested that this retro-cue benefit is related to the concentration of working memory resources on a subset of representations, thereby improving storage and retrieval at the cost of non-cued items. While posterior asymmetries in the EEG, e.g. contralateral delay activity (CDA), can be used to study the active storage of visuo-spatial working memory representations, results on the relation of such asymmetric effects to retro-cue benefits were so far inconclusive. Here, we recorded EEG in a retro-cue working memory task with lateralized items and a continuous performance response. Following either a selective (one out of two items) or neutral retro-cue, participants had to adjust the orientation of a central memory probe to the cued memory item. Selective retro-cues elicited an early posterior contralateral negativity (PCN), anterior directing attention negativity (ADAN), and a later modulation of CDA indicating that active storage was concentrated on the cued information. By dividing all trials into three performance quantiles within experimental conditions, we could further show that high accuracy in the working memory task was associated with a sustained increase of the CDA effect following the retro-cue. This association with performance was not indicated in other correlates of retroactive attentional orienting (e.g. ADAN or posterior contralateral alpha power suppression). These results suggest that focusing resources on the active storage of relevant representations is an important factor regarding retro-cue benefits in working memory tasks.